Zetsubou No Shima:
Seeds of Doubt

Seeds of Doubt, the main Easter egg of Zetsubou No Shima, step by step: the blueprint and the elevator, the three cogs from Lab A, the FlaK 88 and the zipline, the giant Thrasher fight with the Masamune, the ending and the rewards.

3 min read
6 chapters
updated 2026-10-18

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Seeds of Doubt

The main Easter egg of Zetsubou No Shima asks the crew to “save the one”: the original Takeo Masaki, held under the Bunker. It can be done with any number of players, solo included.

Before starting

The Skull of Nan Sapwe, and at least one player with the Anywhere But Here! GobbleGum in their pack. Without that gum, one cog cannot be reached.

Along the way

The power, the KT-4 upgraded into the Masamune, a Gas Mask for every player, the Zombie Shield, every Trial of the Ancients of every player, a bucket, and Seeds.

Step 1: the elevator machinery

In the Living Quarters of the Bunker, by the purple water, use Mesmerize on the torn piece of paper on the wall. Its missing half appears: hidden walls and doors can now be revealed.
In the first room of the Bunker, across from the door to the anti-aircraft platform, stands a broken elevator. Use Mesmerize on the wall to the left of it, in the corner. It vanishes, showing the machinery of the elevator, missing three cogs.

Step 2: the three cogs

The cog above Lab A

Use the Anywhere But Here! GobbleGum, once the elevator door has been revealed. It sends the player into a secret room above Lab A, where the cog lies on the floor near large eggs. A hole in the wall leads back out.

The cog of the plane

Grow Seeds with blue water, fertilised with the KT-4 each round, until a pod gives a FlaK shell. Load it into the back of the FlaK 88 of the anti-aircraft platform, wait for the cargo plane that crosses the sky every two minutes or so, and fire when it lines up with the barrel, since the cannon cannot be aimed. The plane falls with a trail of smoke, and the cog lands outside the Bunker by the large tree, by the back stairs to the zipline at Lab A, or by the meteorite behind Lab B. A missed shot needs a new shell.

The cog of the dock

Electrify the Zombie Shield at the ritual altar. In solo, melee the zipline panel with it, ride the zipline and press melee over the small dock under the line: the player drops straight down onto it. In co-op, one player rides and the other strikes the panel at the right moment. Missing the dock is a fall out of the map.

Step 3: the giant Thrasher

Place the three cogs in the machinery behind the elevator. The elevator works again.
Every player puts on a Gas Mask, or goes down for sure. At least one player holds the Masamune.
Ride the elevator down together. In the corridor, the Masamune clears the three vines blocking the way, at their glowing part.
Behind the last door, a giant Thrasher hangs in a cage. Shoot the spore on one of its arms with the Masamune to start the fight.
Four spores in all, one at a time: between them, survive waves of zombies, spiders and Thrashers, and avoid the vine slams down the middle of the room. The waits are timed and cannot be shortened.
When the fourth spore bursts, the ending plays.

The ending

Primis Takeo finds his older self in a cell. The original Takeo reveals that he was betrayed and imprisoned on the orders of the Emperor himself, and the loyal Takeo sees his whole path built on a lie. “A better tomorrow is only possible if we blow away the ashes of the past.” The original Takeo takes his own life by seppuku, with his younger self as his kaishakunin, and the Summoning Key keeps his soul. “Three down, one to go,” says Dempsey. Richtofen then takes the crew away for a moment and back, to set in motion what he calls an insurance policy.

The reward

Every player gets all the perks of the map: Quick Revive, Juggernog, Double Tap, Speed Cola, Mule Kick, Electric Cherry, Widow’s Wine, Stamin-Up and Deadshot Daiquiri. The perk limit does not grow, so they are lost on going down. The players come back in the arena and ride the elevator up.

Seeds of Doubt

The achievement, 5000 XP and a Gateworm icon on the map selection screen.

The blood vials

From then on, each character carries two blood vials, like Richtofen.

In the First Room

The quest needs the whole island and the Anywhere But Here! GobbleGum. It has nothing to do with a First Room game, which is played doors closed and without gums.